Polishing Aspheric Mirrors of Zero-thermal Expansion Cordierite Ceramics (NEXCERA) for Space Telescope

Abstract

In the next-generation optical satellite, improvement of the thermal stability of the optical system is required.As a mirror material of this system, zero expansion ceramic (NEXCERA) is considered to be a promising material to substitute for conventional zero expansion glass. High precision machining of super lightweight aspheric mirror is crucial for satellite mirror. In this presentation we will present the polishing properties of NEXCERA, the precise polishing of parabolic mirror using sub-aperture tools, and the precise polishing of the hyperbolic mirror using MRF.